氩气雾化制备高温合金粉末的研究

通过对氩气雾化高温合金粉末的制备研究,讨论了粉末的组织、形貌等同制备工艺的关系。结果表明:AA高温合金粉末以球形为主,具有较高的细粉收得率,小于100μm的粉末达到90%以上。粉末氧含量较低,且随着粉末粒度的变小,氧含量有所增加,粉末中含有极少量的空心粉,随着粉末粒度的减小,粉末空心粉数量不断减少,粉末表面也由枝晶组织逐渐过度为胞状晶组织,夹杂主要为非金属氧化物夹杂,含量较少。     

THE HOT EXTRUSION OF METAL POWDERS

Abstract

The procedure of consolidating metal powders by isostatic compaction, canning, and hot extrusion is described. The properties of a number of nickel. base alloys and stainless steels prepared by this method are given.

It is concluded that, even when no precautions are taken to eliminate air (oxygen) from the canned billet, the resulting oxide content of the extruded bar is insufficient to exert a serious influence on the mechanical properties. The corrosion-resistances of certain stainless-steel samples, extruded from powders, were found to be somewhat lower than the corrosion-resistance of equivalent conventionally wrought products.     

金属粉末热挤压

粉末热挤压是粉末冶金与挤压相结合形成的一种特种金属加工工艺,是生产特种材料,诸如铍材、弥散强化材料的主要手段.本文简要介绍了金属粉末热挤压的工艺,实际应用,用金属粉末挤压加工的材料及新发展.     

水雾化钢铁粉末的生产

概述并分析了我国水雾化钢铁粉末的生产和市场状况。介绍了用于烧结机械零件、电焊条和其它领域的水雾化纯铁粉的生产工艺，产品性能及其性能变化的影响因素。     

水雾化铁粉与钢粉新产品的开发

介绍了鞍钢冶金粉材厂近几年来研制开发的水雾化铁粉和钢粉新产品的特性及其应用。新产品包括低合金钢粉、无偏析混合钢粉、易切削钢粉、烧结贝氏体钢粉和阀座粉等 5个系列。     

论预变形铝挤压模具设计

采用常规的模具设计方法，模具上机合格率不高。本文提出预变形模具设计方法，它把模孔形状预先设计成与型材挤压时变形相反的方向，从而获得合格的挤压型材。提高模具的上机合格率。     

ON THERMAL ACTIVATION DURING EXTRUSION OF METAL POWDERS

Abstract

Four aluminium alloy powders were extruded in the temperature range 250–550° C and the strain-rate/flow-stress/temperature relationship analysed in terms of exponential functions. The results of ～400 experimental runs indicate that the powder process is less strain-rate sensitive than is its conventional counterpart. The process is thermally activated and it appears that the rate-controlling mechanism is the climb of edge dislocations or the migration of jogged screw dislocations.     

QMP公司水雾化铁粉与钢粉的生产

本文较全面地介绍了加拿大QMP公司的概况,详细说明了其水雾化铁粉与钢粉的生产流程和化学与物理性能。并扼要记述了该公司的质量管理与研究、开发的成果。     

FACTORS AFFECTING THE GROWTH OF 90/10 COPPER/TIN MIXES BASED ON ATOMIZED POWDERS

Abstract

90/10 bronze components are generally manufactured from mixes based on elemental copper and tin powders, which invariably exhibit growth under production sintering conditions. Previous work has shown that many factors affect growth through their influence on the alloying of tin and copper. Experimental work on atomized copper and tin powders has provided quantitative information on the various factors of significance to growth. It was found that growth was most sensitive to: phosphorus content of copper, fineness of tin, synthetic graphite, addition of prealloyed bronze, green density, heating rate, furnace atmosphere, and sintering temperature. Mechanisms for growth are proposed and preferred methods of growth control suggested.     

HIGH-VELOCITY EXTRUSION FORGING OF BILLETS COMPACTED FROM IRON AND STEEL POWDERS

Abstract

Billets 25 mm in dia. and weighing ～135 g have been compacted from sponge-iron powder using a single-end-pressing technique. A range of densities from 5·6 to 7·2 g/cm³ was produced. The billets were then hot extrusion forged, at high speed, into tensile specimens of gauge-dia. 10 mm, gauge-length 28 mm, and head dimensions of 13 mm dia. × 12·5 mm long. About half the billets were pre-sintered before heating to forging temperature, while others were hot-forged without a pre-sintering stage. The tensile specimens were then tested and selected ones examined metallographically.

The work was extended to investigate the extrusion forging of alloy steel powder.     

东睦新材料公司应用水雾化铁粉的现状

本文介绍了东睦新材料公司应用水雾化铁粉的现状。从我国近年来铁基粉末冶金零件的发展,水雾化铁粉及选择,水雾化铁粉的应用、发展前景及国内水雾化铁粉的现状做了较详细的综述,并对此进行了讨论。     

德国WPL-200,WP-200水雾化铁粉的应用试验

利用工艺试验对德国MannesmannWPL 2 0 0、WP 2 0 0两种水雾化铁粉进行了测试 ,结合主机零件的开发对其材质性能进行了考察 ,结果表明 :两种铁粉性能良好 ,有着广泛的应用前景     

THE SINTERING OF PYROPHORIC POWDERS

Abstract

The room-temperature oxidation behaviour of reactive metal and ceramic powders is reviewed and it is shown that many materials under normal circumstances oxidize to give a limiting film thickness of ～50Å. Since the thickness of oxide films has an important bearing on sintering characteristics the control of oxidation may be essential for some materials and desirable for others.

The oxidation behaviour of uranium carbide and uranium nitride in various concentrations of oxygen and water vapour in argon is described and its effects on the sintering behaviour and composition changes that take place during sintering are considered.

Suitable handling conditions for these materials are provided by glove-boxes filled with argon; there is a brief discussion of the factors that might apply if they were used in other areas of powder metallurgy.

The application of high-purity handling atmospheres in the preparation, handling, and sintering of tungsten powders has given pellets that had densities of 95% theoretical and oxygen contents <10 ppm after sintering in hydrogen at 1550°C.     

THE VIBRATORY PACKING OF POWDERS

Abstract

The objective, in packing particles by vibration, is to increase the density of packing. The main factors affecting the packing of particles in this way are the characteristics of the powder (size distribution, shape, surface condition) and the vibration variables (frequency, amplitude, time). Other factors include segregation by size and shape and also, for a multicomponent powder, by particle density. The wall effect of the container might also be expected to influence the packing in its vicinity. An experimental investigation of some of these variables is here reported.     

熔炼工艺对Cu－Al雾化粉末性质的影响

在雾化制粉工艺中，粉末的纯度和形貌将因活性物质的存在、雾化参数的改变而变化。但对固定的雾化工艺和设备而言，这些因素可视为不变因素，因此，原材料的纯度和熔炼工艺将成为重要的影响因素。本文考察了合金的熔炼方式对Ｃｕ－Ａｌ合金粉末特性的影响。在雾化过程中，有５０％左右的氧化发生在熔炼阶段．氧含量因熔炼方式的不同而不同，文中也探讨了影响粉末形貌的机制．     

FACTORS AFFECTING THE COMPACTION OF TUNGSTEN POWDERS

Abstract

It is difficult to form tungsten powders into compacts by pressure-forming methods. The brittleness of the powder particles causes them to fracture under pressure instead of producing the typical “point welds” exhibited by more ductile particles. Because of this, the powder characteristics such as particle size, size distribution, and particle shape play a most important role in the compacting of tungsten powders.

Both regular- and irregular-shaped particles of tungsten powder are discussed as regards the formation of strong and dense compacts from these powders. Powders composed of irregular-shaped particles gave stronger, but less dense compacts. The effects of particle size and particle-size distribution are also considered. Each of these factors has individual as well as combined effects. It was found that certain critical particle-size distributions produced the densest compacts.

It is concluded that interlocking of particles, which is brought about by surface irregularities, and interfit, which is determined by correct particle-size distribution, are the determining factors in the compaction of tungsten powders.     

关于铝的再生利用探讨

在发达国家,再生有色金属作为一种宝贵的资源,对它的开发和利用得到格外重视,铝的再生利用在世界发达国家中占有重要位置。本文通过对我国目前铝的再生利用现状进行了分析并提出了一些建议和看法。     

THE COMPACTING OF METAL POWDERS BY EXPLOSIVES

Abstract

The paper describes a technique developed for compacting metal powders by the use of detonating explosives under controlled conditions. Aluminium, iron, copper, and steel powders were originally compacted by this means into solid cylinders. Graphite and other non-metal powders have recently been compacted, and modifications have been introduced whereby annular cylinders may be formed. This novel technique may find application in cases where existing mechanical methods of powder compacting are not adequate.